Image detecting capsule device and manufacturing thereof

ABSTRACT

Autonomous/self-powering image detecting systems and their manufacturing technologies are disclosed. An antenna is used to communicate signals. A first energy harvester is used to harvest energy from blackbody radiation, RF signals, movement/vibration, or combination thereof. A power management system is used which controls the energy flow to and from the energy-storage. An image sensor to take the image, a lens, and a transmitter to transmit the images to an outside device are also used in this invention. According to this preferred embodiment, an energy harvester harnessing energy from blackbody radiation from and within the body, is used to extract enough energy to increase the operation time and also to make precision of the image detecting system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of Ser. No. 13/831,812filed on Mar. 15, 2013.

FIELD OF THE INVENTION

This invention is directed to the field of miniaturized wireless biopillfor endoscopy imaging. More particularly, this invention is related tosmall form-factor endoscopic capsule system for increased performance byemploying the use of perpetual energy sources using the body heatsource.

BACKGROUND OF THE INVENTION

The contents of all references, including articles, published patentapplications and patents, if referred to anywhere in this specificationare hereby incorporated by reference.

FIG. 1 shows a schematic showing cross-sectional view of human'sgastrointestinal (GI) system (from mouth to rectum). Diagnosis ofdisease in whole GI tract is very limited using today's invasiveendoscopic technique. Diagnosis of problems in the small intestine hasbeen very difficult. Push endoscopy is the most widely used method ofobserving issues in the small intestine. Push endoscopy is a procedurein which an endoscope is pushed through the mouth through the uppergastrointestinal (GI) tract into the small intestine. Only between 120and 150 cm of the small intestine can be examined with this method. Thesmall intestine is between 3.75 to 8.25 meters so only a portion of theintestine can be observed. Most of the deep intestinal issues orproblems are undiagnosed using standard endoscopy. In addition, standardtechnique is not only painful to patient, but also it takes longer timegoing through whole diagnosis procedure based on this standard endoscopymethod, It is highly desirable to have a method which is takes less orno time for patient in diagnosis procedure.

Recently, wireless video capsules have been developed to be able toobserve the small intestine by taking and transmitting pictures as thecapsule is passed through the small intestine. The capsules usually havean optical dome, lens, illuminating LEDs, CMOS focal array, batteries,electronics, wireless transmitter. The small capsule (the PillCam smallbowel (SB) M2A, GIVEN Imaging Inc.) measured 26 mm in length and 11 mmin diameter. Similar size capsule, named EndoCapsule, marketed byOlympus later is clinically approved. The capsule, when ingested, willtravel down the esophagus through the stomach and through the smallintestine. The battery will last about 6 to 8 hours taking two picturesper second. Pictures are wirelessly transmitted to a data recorder thatis attached to a belt around the waist. The capsule moves too quicklythrough the esophagus to take enough pictures at 2 pictures per second.The capsule also cannot take pictures of a large part of the stomach.The battery will run out before entering the large intestine so thelarge intestine will also not be observed. Rate of transmission throughthe small intestine will depend on the individual patient. A rate toofast beyond 2-3 cm/sec with the current rate of 2 sec/frame could resultin missed detail.

Longer battery life could allow the capsule to take (i) more pictures at(ii) a faster rate and (iii) to last longer also (iv) to observe thelarge intestine. Battery capacity is related to battery technology andsize. Present battery technology that will fit into the capsule islimited to about 60 ma-h. This is a major limitation of making thecapsule more universally accepted. Because of the limitation on batterylife, many approaches for slowing down or strategically stopping thecapsule for more detailed images are infeasible. Slower or morecontrolled mobility would allow more observation down the esophagus andmore time controlled in the stomach. All this additional information iscollected taking additional time that is not available based on currentbattery life.

With extended energy capability there is then no limitation to the timespent stopping and viewing specific areas to better diagnose internalissues. With more energy available some of the disadvantages of thecapsule can be overcome and more feature could be incorporated into thecapsule. For example, features (i) to take more high resolution images,(ii) to retrieve tissue from suspicious areas, (iii) to collect fluidsamples and (iv) perform cytology brushing could be added. All theseadditional features require additional power supply. With that need inmind, this invention is a wireless ingestible capsule which employs useof rechargeable energy sources and/or energy generating sources. Themost importantly, with incorporating the energy generation source is notonly replace the battery, as a major power supply, but it also providesmore advantages to make the capsule more small form-factor, even if itneeds a small battery, medically friendly to all ages of patient.

SUMMARY OF THE INVENTION

According to an embodiment of the current invention, endoscopic systemis an wireless operatable image sensing capsule with an integratedenergy harvester, that includes three mains sections: at least onebattery, section of imaging components, and a section of powerharvesting, power management, and image transmission.

As explained in greater detail below, however, some components may bemoved to different locations or omitted completely. For example, in someembodiments the battery is eliminated, allowing greater flexibility forplacement of the remaining components and reduction of size for theentire capsule.

According to an embodiment of this current invention, an endoscopesystem that is an wireless rechargeable imaging capsule, comprises atleast one energy harvester, a image sensor array, at least one lens, awireless transmitter, an antenna, and a power management unit. Accordingto this invention, the harvester of endoscope system harvest the energyfrom blackbody, and in this case human body heat (e.g. adult .about.36.5C) and/or from the body-vibration, from RF signal, if any, or somecombination thereof, and supply to other optoelectronics components forimage capturing, processing, and transmission. The image sensor arraycan be built and configured to sense light from the visible spectrum upto the mid-infrared spectrum. One lens should be placed so that itconcentrates light in the desired image spectrum on the image sensorarray. If the energy harvester is of a type which absorbs blackbodyradiation, then an additional lens may be used to concentrate theradiation on the harvester.

According to this invention, the image sensor array could be CMOS basedSi image sensor, and or image sensor that can capture the image fromwithin Visible (VIS) to Midwave Infrared (MWIR), or within VIS toLongwave Infrared (LWIR). If CMOS image sensor is used, visible lightemitter is needed to incorporate. According to this invention for otherimage sensor, light emitter may or may not necessary. According to thisinvention, the energy harvester and image sensor are also integratedmonolithically or hybridly which yet to make the whole endoscopy systemmore compact and less power consumption.

According to another embodiment of this current invention, the endoscopesystem includes, includes at least one battery or capacitor, a imagesensor array, a light emitter, at least one lens, a wirelesstransmitter, an antenna, an energy harvesting unit, and a powermanagement unit. The image sensor array can be built and configured tosense light from the visible spectrum up to the mid-infrared spectrum.The energy harvesting unit can be based on absorption of blackbodyradiation, absorption of vibrations, absorption of heat, absorption fromRF signals, or some combination thereof. One lens should be placed sothat it concentrates light in the desired image spectrum on the imagesensor array. If the energy harvester is of a type which absorbsblackbody radiation, then an additional lens can be used to concentratethe radiation on the harvester.

Alternatively, if the image sensor array is built and configured tosense light outside the visible spectrum, like from near visible tomid-infrared, then the battery and LEDs can be omitted. The energyharvested can all be used to run the components alone.

Alternatively, if the image sensor is built and configured to senselight in a broad spectrum, including visible light and non-visible, thenat least one light source s can be used, and therefore a small batterymay be used. The battery could be power supply and also restored theenergy from energy harvester.

According to the invention, the energy harvesting unit can be a singlepixel or an array. Additionally, it may be placed either in the roundedsection of the pill, opposite the imaging components, or it may beformed as a flexible layer on the entire shell of the pill (either alongthe outer side of the shell, or along the inner side), or it may beformed on part of the shell of the pill. Furthermore, whether the energyharvester is within the capsule or along the capsule shell, it may befabricated monolithically on the same wafer as the power managementunit, or separately connected.

According to the invention, the antenna can be formed either inside thepill body or along the shell of the pill either inside or outside of thecapsule. If formed on the shell of the pill (either inside surface oroutside), it can also be formed on top of or underneath an energyharvesting unit layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be better understood by reading the following detaileddescription with reference to the accompanying figures, in which:

FIG. 1 is a schematic showing the cross-section view of human GI system.Internal arrow is showing how our foods are passing from mouth torectum.

FIG. 2A is showing the black-body equation.

FIG. 2B is simulated results of energy available from blackbodyradiation, with temperature (Kelvin) as the parameters.

FIG. 2C is a graph showing the simulated results of the wavelengths ofblackbody radiation at maximum energy.

FIG. 3 is simulated results showing the available energy per squaremeter at various black-body temperatures.

FIG. 4 is a graph showing simulated results of energy conversionefficiency with variation of the temperature.

FIG. 5 is a schematic showing the main parts of the endoscope capsule inthe preferred embodiment, according to this invention.

FIG. 6A is a schematic showing the preferred embodiment of thisinvention for endoscope system, integrating with an energy harvester.

FIG. 6B is a schematic showing an alternate embodiment where the secondenergy harvester harvest energy through vibration and is connected tothe first energy harvester.

FIG. 6C is a schematic showing an alternate embodiment where the secondenergy harvester harvest energy through vibration and is connected tothe power management unit.

FIG. 6D is a schematic showing an alternate embodiment where the firstlens is placed on the inner surface of the shell.

FIG. 6E is a schematic showing an alternate embodiment where the secondlens (118) is placed on the inner surface of said shell.

FIG. 6F is a schematic showing an alternate embodiment where anadditional lens on the imaging section of the lens and is placed on theinner surface of said shell.

FIG. 6G is a schematic showing an alternate embodiment where additionallens on the energy harvesting section of the capsule and is placed onthe inner surface of said capsule.

FIG. 6H is a schematic showing alternate embodiment where two newlenses, one added to the imaging section of the capsule, and a new lensadded to the energy harvesting section of the capsule, where both theselenses, are on the inner surface of the capsule shell.

FIG. 6I is a schematic showing an alternate embodiment where the innersurface of the imaging section of the capsule itself is made of a lens.

FIG. 6J is a schematic showing an alternate embodiment where the innersurface of the energy harvesting section of the capsule itself is madeof a lens.

FIG. 6K is a schematic showing an alternate embodiment where the innersurface of the capsule on both sides is made of lenses.

FIG. 6L is a schematic showing an alternate embodiment where the lens isplaced on the inner surface of the capsule shell and the image sensorarray is placed behind said lens.

FIG. 7 is a graph showing the suitability of various materials as lenseswhich transmit broad radiation wavelengths.

FIG. 8 is a schematic showing an another preferred embodiment of aendoscope capsule system according to this invention, wherein the energyharvesting component is shown as a layer which encases the entiredevice, covering the entire surface.

FIG. 9A is a schematic showing an alternate embodiment of the endoscopecapsule system according to this invention, wherein the antenna as shownas a layer which encases the entire device, and the energy harvestingdevice and power management system then encases the antenna.

FIG. 9B is a schematic showing an alternate embodiment of the endoscopecapsule system according to this invention, wherein the energyharvesting device and power management system as shown as a layer whichencases the entire device, and the antenna then encases the energyharvesting device and power management system.

FIG. 10A is a schematic showing an alternate embodiment of the endoscopecapsule system according to this invention, wherein the antenna as shownas a layer which partially encase the device, and the energy harvestingdevice and power management system then encases the antenna.

FIG. 10B is a schematic showing an alternate embodiment of the endoscopecapsule system according to this invention, wherein the energyharvesting device and power management as shown as a layer whichpartially encase the device, and the antenna then encases the energyharvesting device and power management.

FIG. 11 is a schematic showing an alternate embodiment of endoscopecapsule system according to this invention.

FIG. 12 is the graphs showing (A) cut-odd wavelengths, and (B)absorption coefficient for HgCdTe depending on the percentage of Cd.

FIG. 12C is a graph showing the quantum efficiency of HgCdTe device asan example, according to this invention.

FIG. 13 is a schematic showing for the most basic description of how thecomponents of the invention are to be connected according to thisinvention.

FIG. 14 is a schematic showing details of one possible arrangement ofcomponents, according to this invention.

FIG. 15 is schematic showing the cross-sectional view of the energyharvester as a single element, according to this invention.

FIG. 16 are the schematics showing the embodiment of FIG. 15 externallyconnected to a power management unit through the use of indium bumpshaving connection: (A) one side and (B) both side with bumps, accordingto this invention.

FIG. 17A is an alternate embodiment of the energy harvester, wherein twodiodes are stacked on top of one another and connected/separated by abuffer layer, according to this invention.

FIG. 17B shows the device of FIG. 17A externally connected to a powermanagement unit through the use of indium bumps, according to thisinvention.

FIG. 18A is an alternate embodiment of the energy harvester, whereinmore than one harvester element are placed side by side monolithicallyto make a energy harvester, according to this invention.

FIG. 18B shows the device from FIG. 18A externally connected to a powermanagement unit through the use of indium bumps, according to thisinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Some embodiments of the current invention are discussed in detail below.In describing embodiments, specific terminology is employed for the sakeof clarity. However, the invention is not intended to be limited to thespecific terminology so selected. A person skilled in the relevant artwill recognize that other equivalent components can be employed andother methods developed without departing from the broad concepts of thecurrent invention.

As mentioned, earlier, one disadvantage limiting capsule capability isbattery life. Based on size of the capsule, batteries that could be usedin the capsule have only enough energy to support about 8 hours withvery less functionality. This 8 hrs. time is adequate to pass throughthe small intestine but not the large intestine. If battery life can beextended beyond their normal 6-8 hours capsule operation up to 72 hours,the large intestine can also be evaluated. Even longer battery lifewould allow imaging throughout the system at normal speed as well asslowed speed. Without external control 2 frames per second are captured.Methods of motion control, will result in more pictures taken and aslower passage through the small intestine consuming more battery life.

Constrained by size that can be conveniently swallowed, batteriescurrently used fit in the 11 mm by 26 mm capsule size. A typical batteryused is a silver oxide battery similar to battery number 394 fromEnergizer. This battery has 60 ma-h capabilities with a circumference of9.5 mm and a thickness of two cells of 7.2 mm. Higher capacity batterieswould have either larger circumference or would be thicker.

According to this invention, an approach to extend the battery life isto replace batteries with rechargeable batteries and/or replace byenergy harvester. In standard capsule, an energy source for rechargingthe battery as the capsule migrates through the body is then necessaryand it would be more painful to patient. According to this invention,the battery will be replaced by energy harvester, which helps to makethe capsule more smaller, easier to swallow and could have morefunctionalities. The using of this energy harvester could also allowelimination of the batteries if the capsule requirements will matchharvested power. Capsule size reduction would result with 8 mm ofbattery removed.

Although several sources of energy within the human body are available,the preferred embodiment of this invention utilizes the energyharvesting from blackbody radiation. The human body radiates energy thesame as any blackbody. This radiation energy is in the infraredwavelength. Radiation from a blackbody at a specific temperature isdetermined by Planck's blackbody radiation law, as illustrated in FIG.2A and its simulated results at various temperature are shown in FIG.2B. In this equation as illustrated in FIG. 2A, c=speed of light,k=Boltzman's constant, h=Planck's constant, .lamda.=wavelength, andT=temperature in Kelvin. As the temperature increases, the wavelength atthe peak energy decreases. FIG. 2C shows the simulated results of peakenergy wavelengths with functions of the temperature. The total amountof energy generated at a specific temperature are shown in FIG. 3, whichdepicts that available harvesting energy at body temperature of 310Kelvin is about 500 watts per square meter.

According to this invention, there are also several other potentialsources of energy within the body. One example is body vibration createddue to the daily activities, other surrounding issues, and/or otherorgan functioning (e.g. heart, vein, artery etc.), from which energycould be harvested and feed to the system According to this invention,mechanisms for harvesting such energy might be electromagnetic (0.05Watts per square meter), piezoelectric (6 Watts per square meter), orelectrostatic (0.04 Watts per square meter). Another example is bodyheat, using a mechanism for thermoelectric harvesting. Alternatively,energy can be harvested from RF signals from outside the body. Thesignal from the imaging capsule is sent to an external receiver,typically held close to the body. RF signals from this receiver can helppower the capsule. Although blackbody radiation is discussed in the mostdetail below, according to this invention, any of the above sources ofenergy can also be utilized, especially in combination.

Power consumption for current capsules is 25 mwatt. At 25 mWatt, the 60ma-h (60 ma-h.times.3 v=180 mWatt) battery will be consumed in 7.2hours. This can be extended indefinitely with the ability to harvestgreater than 25 mwatt of continuous blackbody radiation. According tothis invention there is 500 Watts per meter available to be harvestedwith in the human body. The preferred capsule diameter is 11 mm so theharvesting device should fit within this diameter. The peak wavelengthfor maximum energy for human body temperature, 310 Kelvin, is 9 microns.This maximum energy peak wavelength can be derived by determining themaximum energy wavelength of Planck's radiation law equation as shown inFIG. 2A. From the calculated results, as shown in FIG. 3, it gives theentire amount of blackbody energy generated and available for harvestingat a specific temperature. At 310K, approximately 500 W/m.sup.2 can beharvested.

This energy harvester which could be integrated into the capsule, isformed using the semiconductor material. Adjusting a material that wouldharvest at a peak frequency of 9 microns results in high intrinsiccarriers and thus high dark current. Devices adjusted to high infraredwavelengths are normally operated at low temperatures (77 k). Acompromise and workable solution is to adjust to the near infrared rangethat has less intrinsic carriers and lower dark current at 300K. Apotential tuning range is between 3 microns and 5 microns. Within thisrange the harvested energy for different harvest conversion efficienciesis shown in FIG. 4. If 50% efficiency harvesting is achieved, 47 wattsper square meter is harvested. According to this invention, this harvestcapability translates to 0.047 mwatt per square millimeter. The area ofa harvest device that fits into a 7 mm diameter capsule (remember thatthe final goal is reduced size) would be 6.9 mm.times.6.9 mm=47.61square millimeters resulting in 2.23 mWatt harvested. This would supplypower to continuously charge the battery and have continuous capsuleoperation through put the digestive tract once the power of capsuleelectronic components is reduced. Focal plane array, read out integratedcircuit and communication devices can be redesigned to consume less than0.5 mwatt each by lower voltage and weak inversion operation resultingin a total of 1 mWatt. LED power consumption will be the main power usedin short bursts. The LED's will be pulsed and need high energy (60 mWper LED times four LED's equals 240 mWatt) for short duration. Shortdurations are only for less than 1 msec three times every second ifrecording visible, infrared illuminated and dark every second. If onlyilluminating 1 msec three times per second then average power would onlybe 0.240 mw.times.3 or 0.72 mWatts and be well within the capability ofharvesting. Total estimated operating average operating power would be0.5 mWatt.times.2+0.72 mWatt=1.72 mWatt. As long as LED's are used forvisible and infrared illumination a storage medium would be necessary tosupply the temporary peak power surge. If a capacitor was made with thinCMOS gate oxide in the 47 square millimeter area there would be 15microfarads of capacitance. Using I dt=C dv it can be shown that with 15microfarads of capacitance would cause the voltage to be depleted. Idt=240 mWatts/3 v.times.1 msec=80 .mu.A-sec=15 .mu.f.times.dv. dv=5.33volts. Batteries will need to be used until a solution of capacitancemore than an order of magnitude greater is available.

FIG. 5 shows the generalized preferred embodiment of endoscopy capsulesystem, according to this invention. On one end of the capsule is theimaging section 98, in the middle is the energy storage/managementsection 100, and on the opposite side is the energy harvester andcommunication components 101.

FIG. 6A shows the preferred embodiment of this invention for endoscopesystem, integrating with an energy harvester. The middle section 100 isthe power storage section connected to management system (not shown herein details) which includes electronics comprising with inverter,storage, and energy harvester, explained later. As a storage, capacitoror rechargeable battery or their combination is integrated and placed inmiddle section 100. In one end of the capsule all the signal processingelectronics and part or whole of the antenna are housed. Main componentsthis consists of an antenna 102, a transmitter 104, and others (notshown here). The imaging section 98 comprises a focal plane array(a.k.a. image sensor) 106 with a CMOS readout integrated circuit builtin, emitter source (e.g. LED) 108 provide illumination for imagingpurposes, while a lens 110 focuses light in the desired spectrum on thefocal array. Power for the focal array 106 and light emitter 108 isprovided by the energy storage section 100. The energy storage section100 is placed in the body of the capsule next to the imaging section,and takes up most of the space within the capsule. Making smaller willnot only makes the capsule more compact, but also reduces the powerconsumption which enables it to capture more images and include morefunctionality. According to this invention, energy harvester, could bewith or without battery. If battery is used, the only one battery mayneed. The energy harvester 112 and power management unit 114 are placedfor optimal energy absorption and connected to each other.Alternatively, the power management unit 114 can be integrated into theenergy harvester 112 itself, as discussed in more detail below. A lens118 focuses infrared light on the energy harvester 112, and can beformed from any material which is suitable for this purpose. Forexample, magnesium fluoride, calcium fluoride, zinc selenide, bariumfluoride, AMTIR I, arsenic fluoride, zinc sulfide, sapphire, silicon,germanium, or some combination thereof.

FIG. 6B and FIG. 6C are schematics showing alternate embodimentsaccording to this invention, wherein the same parts in FIG. 6B and FIG.6C represent the similar parts in FIG. 6A, so that repeated explanationis omitted here. The only difference between FIG. 6A with FIG. 6B andFIG. 6C, is that an additional energy harvester (second energyharvester) 120 is located within the capsule in FIG. 6B and FIG. 6C. Thesecond energy harvester 120 in FIG. 6B harvest energy throughmovement/vibration. In FIG. 6B the second energy harvester 120 isconnected to the first energy harvester 112. Alternatively in FIG. 6Cthe second energy harvester 120 is connected to the power managementunit 114. FIG. 6D and FIG. 6E are schematics showing alternateembodiments according to this invention, wherein the same parts in FIG.6D and FIG. 6E represent the similar parts in FIG. 6A, so that repeatedexplanation is omitted here. The only difference between FIG. 6A withFIG. 6D and FIG. 6E, is the location of one of the lenses, either thefirst lens (110) or the second lens (118). In FIG. 6D the first lens isplaced on the inner surface of the shell and in FIG. 6E, the second lens(118) is placed on the inner surface of said shell. For theseembodiments to be possible, the lens would have to be of flexiblematerial. FIG. 6F, FIG. 6G and FIG. 6H are schematics showing alternateembodiments according to this invention, wherein the same parts in FIG.6F, FIG. 6G and FIG. 6H represent the similar parts in FIG. 6A, so thatrepeated explanation is omitted here. The only difference between FIG.6A with FIG. 6F, FIG. 6G and FIG. 6H, is that new lenses are added toeach of these embodiments (FIG. 6F, FIG. 6G and FIG. 6H) and placed onthe inner surface of the shell. In FIG. 6F, a new lens 122 has beenadded to the imaging section of the lens and is placed on the innersurface of said shell. In FIG. 6G, a new lens 124 has been added to theenergy harvesting section of the capsule and is placed on the innersurface of said capsule. In FIG. 6H a new lens 122 has been added to theimaging section of the capsule, and a new lens 124 has been added to theenergy harvesting section of the capsule. Both these lenses, 122 and 124are placed on the inner surface of the capsule shell. FIG. 6I, FIG. 6Jand FIG. 6K are schematics showing alternate embodiments according tothis invention, wherein the same parts in FIG. 6I, FIG. 6J and FIG. 6Krepresent the similar parts in FIG. 6A, so that repeated explanation isomitted here. The only difference between FIG. 6A with FIG. 6I, FIG. 6Jand FIG. 6K, is that the in these embodiments, the capsule shell itselfis made of lenses. In FIG. 6I, the inner surface of the capsule itself(the imaging section of the capsule) is made of a lens 126. In FIG. 63,the inner surface of the capsule itself (the energy harvesting sectionof the capsule) is made of a lens 128. In FIG. 6K the inner surface ofthe capsule on both sides is made of lenses, the inner surface of thecapsule in the imaging section is made of a lens 126 and the innersurface of the capsule in the energy harvesting section is made of alens 128. FIG. 6L, is the schematic showing alternate embodimentaccording to this invention, wherein the same parts in FIG. 6L,represents the similar parts in FIG. 6A, so that repeated explanation isomitted here. The only difference between FIG. 6A with FIG. 6L, is thatin this embodiment, the location of the lens or the image sensor arrayor both the lens and image sensor array is different. In FIG. 6L, thelens 110 is placed on the inner surface of the capsule shell and theimage sensor array 106 is placed behind said lens. For FIG. 6L, to bepossible, both the lens and image sensor array would have to be made offlexible material

As long as the connections described above are maintained, the placementof the various components can be placed in many different ways. Forexample, the focal array 106 or energy harvester 112 can be formed aslayers which cover all or part of the outer shell of the capsule. Such achoice increases the surface area of both devices and improvesperformance of the device as a whole. Additionally, the antenna might beformed as a layer disposed below or on top of the focal array orharvester layer. If the antenna is formed on top, then it should beformed from a material which does not absorb wavelengths of interest,otherwise it might hinder performance of the device as a whole. Anycombination of the above descriptions is possible. FIG. 7 shows a graphof various possible materials and their suitability for transmitting IRwavelengths. The transmitter 104 and antenna 102 are also located in thecapsule section 101. The power management unit 114 is connected to theenergy storage section 100 through connection 116 to control flow ofenergy to and from the energy storage 100, and then all other componentswhich require power (the transmitter 104, focal array 106, and lightemitter 108) are connected to the power management unit 114.

FIG. 8 is a schematic showing the alternate endoscope capsule in thepreferred embodiment, according to this invention, wherein same numeralsare used for the similar parts, so that repeated explanation is omittedhere. In this preferred embodiment where the focal array 106 remains thesame, but the energy harvester 112 and power management unit 114 areintegrated and formed as a layer which covers the entire outer surfaceof the pill. FIG. 9A is another alternate embodiment, except where theantenna 102 is also formed as an outer layer, placed below the energyharvester 112 and power management system 114. FIG. 9B is anotheralternate embodiment, except where the energy harvester 112 and powermanagement system 114 are also formed as an outer layer, placed belowthe antenna 102. FIG. 10A is another embodiment of this endoscopiccapsule invention, where the antenna 102 layer is formed on the outerlayer and encased by the energy harvester 112 and power managementsystem 114 layer cover the entire surface except for the imagingsection. FIG. 10B is another embodiment of this endoscopic capsuleinvention, where the energy harvester 112 and power management system114 layer are formed on the outer layer and encased by the antenna 102layer cover the entire surface except for the imaging section. Thisembodiment might be favorable in situations where the materials used forthe antenna and/or energy harvester might block the wavelengths whichthe imager is designed to detect.

As an another example of the embodiments (not shown in here), the focalarray 106 might be a layer which covers the battery section and imagingsection, while the energy harvester 112 might be a layer which coversthe remaining surface area without overlapping the focal array 106. Theantenna might then be a layer which is located under or over one or bothof the layers 112 and 106. As another example, the focal array 106 andenergy harvester might be layers which cover the entire pill, stacked ontop of one another. The antenna could then be placed inside, or formedas a layer under the layers 106 and 112, over the layers 106 and 112, oreven placed between the layers 106 and 112. FIG. 11 is a schematicshowing a another preferred embodiment of this current invention forendoscope capsule system, wherein the same numerals represent thesimilar parts as explained in FIGS. 8, and 8-10, so that repeatedexplanations are omitted here. According to this invention, the batteryis completely omitted. In this case, the harvester generates energy andfeed directly to the system. This is system can be with and withoutlight emitters. As Light emitters consume more power, light emitter canbe omitted. As explained earlier, harvesting power is enough to take theimage, signal processing, and transmitting to outside. The light emitter108 is only necessary when the focal array 106 is designed to sensevisible light. If, instead, the focal array is designed to sense outsidethe visible spectrum only, such as infrared imaging, then the lightemitter can be omitted and the device as a whole can function on theharvested energy alone. The embodiment in FIG. 11 shows theendoscope-capsule as much reduced in size, but alternatively, the emptyspace in the middle can be utilized in a number of ways, as discussedfurther below.

The preferred embodiment of this invention for endoscope capsule systemincludes several sections, and othe of them is the energy harvesterdevice and its integration with power management system which can reducethe size and make it longer to operate more than 10 hrs. or so capturingGI's image, as it passes. The harvester technique is explained below, asan example, but not limiting the invention. For simplicity, we wouldprovide an example in related to harvester which is made using highwavelength absorption material such as HgCdTe based material systems.However, it can be related to other semiconductor materials such asInSb, etc.

A preferred material for infrared harvesting is Mercury CadmiumTelluride (HgCdTe). HgCdTe's bandgap can be tuned between 0.8 .mu.m to25 .mu.m. It has been determined that the bandgap can be adjusted byvarying the percentage of Hg versus Cd. The equation showing thisrelationship is Eg=−0.302+1.93x−0.81x.sup.2+0.832x.sup.3+(5.35.times.10.sup.4)T(1−2x) where x is the amountof cadmium (Cd). This equation is plotted in FIG. 12A. The absorptionspectra of the HgCdTe with various Cd contents are calculated and it isshow in FIG. 12B. Adjustment of cadmium versus mercury can result in areasonable implementation that has the ability to harvest wavelengthsfrom 3 micrometer to 10 micrometer. The upper limit of 10 micrometer waschosen to maintain a reasonable forward voltage. There are severalfactors that contribute to infrared harvesting efficiency. The abilityof a material of absorb energy in the wavelength of available energy isa key factor. This key factor determining the net conversion efficiencyof harvester is quantum efficiency (QE). (QE) is the probability that anincident photon of energy Egwill deliver an electron to the externalcircuit. QE varies per wavelength for different solar harvestingtechnologies. FIG. 12C shows how QE varies in HgCdTe across wavelengths.Other factors affecting conversion efficiency are cell layerthicknesses, contact resistances and leakages To achieve the bandgapupper limit of 10 .mu.m, 17% Cadmium versus 83% mercury is used. Onceenergy is harvested, conditioning of that energy must be done to supplyvoltage and current to devices and charge batteries. Power managementdevices designed to interface between the infrared harvesting structureand output device can be designed with current CMOS technology. To haveversatile output voltage range, a 0.35 .mu.m process with high voltageoptions up to 10 volts would be used. This will allow internal harvestedvoltages to go beyond 3 volts and be regulated to a desired 3 voltoutput.

According to this invention, if 30% efficiency of harvesting isachieved, 125 Watts per square meter is harvested. This harvestcapability translates to 0.125 mWatt per square millimeter. The area ofa circular harvest device that fits into the 11 mm diameter capsulewould be 9.5 mm.times.9.5 mm.times.3.14=283 square millimeters resultingin 35.4 mwatt harvested. This would supply substantial power tocontinuously charge the storage element (e.g. capacitor or battery) andhave continuous capsule operation throughout the digestive tract.Alternatively, if the harvest device is formed as a layer all along thecapsule shell as well as a circular disk, harvested energy could be evenhigher. A harvester which is a layer covering only the battery sectionalone will have a surface area of approximately 275 square millimeters.Combined with the circular disk harvester, this would result inapproximately 69.78 mwatt harvested.

The specific structure of the preferred embodiments, as explained inFIGS. 5 to 12 is highly variable. Although the connections must beconstant within every variation, the specific placement of eachcomponent can be changed in many ways, especially if the battery is beeneliminated completely. FIG. 13 is a schematic showing the very basicmethod of connecting the components. An energy harvester and powermanagement unit are integrated into a single unit, either monolithicallyformed on the same wafer, or fabricated separately and then stacked andconnected with metal bumps. A energy storage (e.g. battery) is thenconnected to the power management unit, and the focal array andcommunication device are separately connected to the power managementunit. The components must all be connected in roughly the same way. Thepower management unit and energy harvester are connected to form anintegrated system. The power management unit then connects to the energystorage (e.g. battery or capacitor) to store/recharge and distribute theenergy to the other components of the capsule. Alternatively, the powermanagement unit might be connected only to the batter and harvester,while all of the other components needing power connect directly to thebattery as well.

FIG. 14 shows an alternate schematic for a method of connecting thecomponents, according to this invention. In this embodiment, theintegrated power unit comprises an energy harvester, a batterycontroller, and a DC-DC converter. The harvester supplies power to theenergy storage (e.g. capacitor or battery) controller, which isconnected to the DC-DC converter and to an external battery. The DC-DCconverter is connected to the external focal array and communicationcomponents. All components as shown in FIG. 14, can also be made tosicglec chip, sizes of 1 to 5 sq. mm with thickness of less than 1 mmusing CMOS technology.

FIGS. 13 and 14 are meant to serve as examples for how to connect thevarious components, and are not intended to be limiting. Other obviousvariations would occur to a person skilled in the art.

According to this invention, the energy harvester can be structured manydifferent ways. The device is structured as shown in FIG. 15i . Thedevice is built on substrate 200, and consists of semiconductor layers202 and 204. Those layers are doped opposite (either 202 is p-doped and204 is n-doped, or vice versa). Additional layers of p or n dopedmaterial can also be inserted, or an intrinsic layer to form a p-i-njunction (not shown in here). Although pn-junctions and pin-junctionsare favorable, other types of junctions are possible as well (notshown). For example, the device might utilize Schottkey-junctions, nBn,nBP, pB-i-n structures, quantum wells, quantum dots, or a combination.Electrical contacts 206 and 210 are formed such that each contactconnects with a different semiconductor layer, and they are electricallyinsulated from each other with passivation material 208. Substrate 200can be left as a support layer, doped to be part of the junction, etchedout, or it can act as a power management system if formed from anintegrated circuit is made on the substrate. If the integrated circuit(may make to power management system) is used as the substrate forenergy harvester, then the harvester is fully integrated with the powermanagement system, and external connection is unnecessary. If theintegrated circuit (part of the power management unit) is not integratedinto the harvester, then the harvester must be connected externally tothe power management unit. FIG. 16A shows how the power management unit212 would be connected to the energy harvester through use of indiumbumps 214. The electrodes 216 in power management unit connects theenergy harvester to other component such as image sensor and lightemitter (if any), and also to the signal processing circuit fortransmission (not shown here). Other integrated circuit for image sensorand also for the transmission all could be also integrated into onecircuit (not shown here), according to this invention. FIG. 16B is analternate embodiment according to this invention, wherein all numeralsas explained in FIG. 15A, represents the same parts, so that repeatedexplanation is omitted here. Only difference is that the hybridintegration can also be hybridly connected to other integrated circuit,and or image sensor through the bumps 214, placed in other side of powermanagement unit 212.

The preferred embodiment utilizes primarily HgCdTe, as an example,wherein HgCdTe is manufactured on an undoped silicon substrate 200 witha deposited layer of CdTe (not shown). The CdTe is a buffer layer toreduce stress between the silicon substrate and HgCdTe substrate, andcan be doped or not. Doping with iodine creates n-type HgCdTe as thefirst layer 202. Doping with arsenic creates the p-type HgCdTe on top,204. Metal Ohmic contacts 206 and 210 are made to the n-type and p-typedevices on the top side, insulated from each other with passivationlayer 208. Illumination is from the bottom silicon side. All infraredwavelengths between 1 .mu.m and greater than 10 .mu.m will pass throughthe silicon CdTe substrate. Up to 1 .mu.m of wavelength energy does notpass to the HgCdTe since it is absorbed by the CdTe and also Sisubstrate. This configuration creates a pn-junction sitting on top of aSilicon substrate, but many other configurations can be used instead.For example, pin-junctions, Schottkey junctions, quantum wells, quantumdot junctions, nBn detectors, or a combination. Additionally, thep-layer and n-layer need not be configured in the manner that ispictured. The layers could be easily reversed, and they need not besingle layers.

FIG. 15. shows the structure of a single diode (energy harvester). Itmight alternatively be placed in an array, or in combination with morediodes. The number of diodes in parallel or series will depend ondesired current and voltage. The voltage in the case of the capsuleharvesting structure will be above 4 to 5 volts to compensate for dropacross the protection diode and to give more headroom to the powermanagement unit.

FIG. 17A shows such a configuration for energy harvester 220, where twodiodes are connected in series on the same wafer, according to thisinvention wherein same numerals represent the similar parts, asexplained in FIG. 15 and FIG. 16, so that repeated explanation isomitted here. Any number of diodes can be connected in series and inparallel, and this figure is intended only as an example, not alimitation. When multiple such junctions are used, they can be formedfrom the same materials (HgCdTe) or different ones. If differentmaterials are used within the same wafer, a buffer layer (or several)might be required in order to minimize lattice mismatch. If the diodesforming energy harvester 220, are connected through Indium bumpsinstead, as illustrated in another embodiment, as shown FIG. 17B,according to this invention, where buffer layers are not necessary.

FIG. 18A shows the single-diode element for energy harvester as placedin an array 230 according to this invention wherein same numeralsrepresent the similar parts, so that repeated explanation is omittedhere. To achieve this, the harvester element might be formed separatelyand then connected, or they can be formed on the same wafer by formingmultiple contacts for one semiconductor layer to form the harvester 230,while keeping one common contact for the other semiconductor layer.Alternatively, if placed in an array, each pixel need not be identical.Each harvester element comprising different types of diodes or differentmaterial types can also be utilized in order to expand the spectrumabsorbed. FIG. 18B shows how such an array might be connected to anpower management integrated circuit unit in much the same way as wasshown in FIGS. 16B, and 17B

The CMOS power management unit can be connected to the energy harvesterin a number of ways. The simplest is to connect it to the ohmic contactsby way of Indium “bumps.” Alternatively, the power management circuitcan be integrated directly into a Silicon substrate, which the energyharvester is then formed on. In this way, the power management unit andenergy harvester are both contained on the same wafer, and additionalconnection is not needed. Alternatively, if multiple diodes connected inseries or parallel are being used, the power management unit might beintegrated into one or more diodes, and then another (or multiple) diodeis connected to the integrated system through Indium bumps.

As can be seen, the energy harvester structure is incredibly variable,depending on the specific needs of the structure being used. Onceformed, the harvester and power management unit can also be furtherthinned in order to save space within the capsule. Preferably thecombined energy harvester and power management unit will be less than150 micrometers thin, but the preferred size can vary depending onplacement and space available. An advantage of thinning out the Siliconsubstrate is reducing absorption of light in the spectrum of interest.

The focal array lens and infrared lens can alternatively be integrateddirectly into the shell of the capsule. Typically capsules are formedfrom clear plastic, but they might instead be formed from materialsappropriate for use as lenses and then designed in such a way as toconcentrate light on the focal array or energy harvesting device, orboth.

As alternatives to the above preferred embodiment, the capsule accordingto this invention, can be formed from many different materials, and canbe configured to absorb in different wavelengths. For example, the lightemitter (e.g. LED) is only needed when imaging within the visiblespectrum. However, the focal array can also be formed from materialswhich allow for non-visible imaging, such as IR. If this is done, thenthe either light emitter sensing that IR wavelengths, or nor lightemitter are not necessary. In the case of capsule without light emitter,the IR image sensor is used which provide thermal imaging when capsulepasses through the GI.

The light emitter is the main source of power draw within the capsule,so eliminating them allows for use of a smaller energy storage (e.g.battery), or even elimination of the energy storage altogether. Withthis in mind, many more options open up. The capsule can be made smallerand easier to swallow, or the extra space can be used for additionalfeatures, such as tissue sampling or pH testing. Alternatively, theextra space can be used for energy harvesters which are bigger, whichopens the possibility to use the alternative harvesters mentionedpreviously. Although these alternatives are currently not as effectiveas the blackbody radiation harvester, they may be preferable in someembodiments due to cost of manufacturing or other factors.

Along a similar idea, the imaging focal array might utilize acombination of visible imaging and UV or IR imaging. In this case, somelight from an light emitter might be needed, but not as much as if thefocal array is purely visible imaging. In this case, the battery can bereduced but likely not eliminated altogether.

Whereas many alterations and modifications of the present invention willno doubt become apparent to a person of ordinary skill in the art afterhaving read the foregoing description, it is to be understood that theparticular embodiments shown and described by way of illustration are inno way intended to be considered limiting. Therefore, reference to thedetails of the preferred embodiments is not intended to limit theirscope. Although the invention has been described with respect tospecific embodiment for complete and clear disclosure, the appendedclaims are not to be thus limited but are to be construed as embodyingall modification and alternative constructions that may be occurred toone skilled in the art which fairly fall within the basic teaching hereis set forth. Although the invention has been described with respect tospecific embodiment for complete and clear disclosure, the appendedclaims are not to be thus limited but are to be construed as embodyingall modification and alternative constructions that may be occurred toone skilled in the art which fairly tall within the basic teaching hereis set forth.

What is claimed is:
 1. An imaging capsule system comprising: a capsuleshell, and; an electro-optical system, wherein the electro-opticalsystem comprises: a first energy harvester, wherein said energyharvester is designed to harvest energy from surrounding vibration,movement, body heat or combination thereof; an image sensor, whereinsaid image sensor detects non-visible light; a first lens; wherein thefirst lens is a part of the capsule shell, wherein the first lensfocuses the non-visible light to the image sensor; a second energyharvester, wherein the second energy harvester harvests energy from aninfrared radiation, wherein the second energy harvester comprises ofmore than one diode connected in series and wherein the second energyharvester supplies the energy to the electro-optical system, and; asecond lens, and: wherein the second lens is designed to focus theinfrared radiation to the second energy harvester; a signal processingelectronics, wherein the signal possessing electronics comprises anantenna and a transmitter; wherein the electro-optical system is housedin the capsule shell, and wherein the capsule shell is swallowable. 2.The electro-optical system according to claim 1, further comprising anadditional image sensor designed to detect visible radiation.
 3. Theelectro-optical system according to claim 1, further comprising anenergy storage device that is a battery or a capacitor.
 4. Theelectro-optical system according to claim 1, further comprising at leastone light emitter.
 5. An imaging capsule system comprising: a capsuleshell, and; an electro-optical system, wherein the electro-opticalsystem comprises: a first energy harvester, wherein said energyharvester is designed to harvest energy from surrounding vibration,movement, body heat or combination thereof; an image sensor, whereinsaid image sensor detects non-visible light; a first lens; wherein thefirst lens is a part of the capsule shell, wherein the first lensfocuses the non-visible light to the image sensor; a second energyharvester, wherein the second energy harvester harvests energy from aninfrared radiation, wherein the second energy harvester comprises ofmore than one diode connected in series and wherein the second energyharvester supplies the energy to the electro-optical system, and; asecond lens; wherein the second lens is designed to focus the infraredradiation to the second energy harvester; a signal processingelectronics, wherein the signal possessing electronics comprises anantenna and a transmitter, and; a power management system, wherein thepower management system controls the flow of energy to the signalprocessing electronics and image sensor, wherein the electro-opticalsystem is housed in the capsule shell, and wherein the capsule shell isswallowable.
 6. The electro-optical system according to claim 5, furthercomprising an additional image sensor designed to detect visibleradiation.
 7. The electro-optical system according to claim 5, furthercomprising an energy storage device that is a battery or a capacitor. 8.The electro-optical system according to claim 5, further comprising atleast one light emitter.
 9. An imaging capsule system comprising: acapsule shell, and; all electro-optical system, wherein theelectro-optical system comprises: a first energy harvester, wherein saidenergy harvester is designed to harvest energy from surroundingvibration, movement, body heat or combination thereof; an image sensor,wherein said image sensor detects non-visible light; a first lens;wherein the first lens is a part of the capsule shell, wherein the firstlens focuses the non-visible light to the image sensor; a second energyharvester, wherein the second energy harvester harvests energy from aninfrared radiation, wherein the second energy harvester comprises ofmore than one diode connected in series and wherein the second energyharvester supplies the energy to the electro-optical system, and; asecond lens; wherein the second lens is designed to focus the infraredradiation to the second energy harvester; a signal processingelectronics, wherein the signal possessing electronics comprises anantenna and a transmitter; a power management system, and; an energystorage device, wherein the energy storage device is located between theenergy harvester and the image sensor, wherein the power managementsystem controls the flow of energy to the signal processing electronicsand image sensor, wherein the power management system comprising of abattery controller and a dc-dc converter; wherein the electro-opticalsystem is housed in the capsule shell, and wherein the capsule shell isswallowable.
 10. The electro-optical system according to claim 9,further comprising at least one light emitter and an additional imagesensor designed to detect visible radiation.
 11. The imaging capsulesystem according to claim 9, further comprising an additional energyharvester that harvests RF radiation.
 12. The electro-optical systemaccording to claim 9, further comprising an energy storage device thatis a battery or a capacitor.